Tracking Moose Antler Size Changes Over 20 Years Using Public Photos

Jenn Hoskins
17th May, 2024

Tracking Moose Antler Size Changes Over 20 Years Using Public Photos

Image Source: Tatiana (photographer)

Key Findings

  • In Poland, a hunting ban from 2001 led to a significant increase in the moose population from 1,800 to over 20,000 individuals
  • During the hunting ban, the probability of observing cervina antler types decreased, while intermediate and palmate antler types increased
  • The mean number of antler tines and the overall antler size index both significantly increased over the study period, likely due to the aging of the population released from hunting pressure
Hunting directly impacts the population dynamics of ungulates and can significantly affect the quality of phenotypic traits such as horns or antlers. In Poland, following a demographic collapse in the 1990s and the introduction of a hunting ban in 2001, the population of moose (Alces alces) has increased from 1,800 to over 20,000 individuals, recolonizing its former range. Researchers from the Polish Academy of Sciences[1] analyzed changes in antler size and shape in this cervid between 2005 and 2021 based on photos of male moose and antler casts provided by photographers or available on social media. The study found that during the hunting ban, the probability of observing the cervina antler type significantly decreased over time, from 47% in 2012 to 28% in 2021. Meanwhile, the probability of observing the intermediate and palmate antler types significantly increased from 44 to 53% and from 9 to 19%, respectively. The mean number of tines significantly increased from 3.2 in 2005 to 4.7 in 2021, and the antler size index significantly increased from 3.4 to 3.9. The most likely mechanism behind the observed changes could be the aging of a population released from hunting pressure. This study ties into earlier research on the effects of human harvest on wild populations. For example, it has been established that human harvest of phenotypically desirable animals can impose selection that reduces the frequencies of those desirable phenotypes[2]. The observed increase in antler size and complexity in the Polish moose population during the hunting ban aligns with the idea that curtailing harvest can reduce the intensity of selection against desirable traits, allowing them to become more prevalent over time. Moreover, the regional variation in antler size observed in the study is likely related to differences in environmental conditions. This finding is consistent with earlier studies that have shown how spatio-temporal variation in resource availability can lead to a variety of animal movement strategies and phenotypic traits[3]. For instance, in moose populations in Europe, habitat patchiness has been associated with different movement behaviors, which in turn can influence phenotypic traits such as antler size and shape. The study also highlights the value of passive citizen science in contributing to our understanding of ecological trends and the quantification of population patterns. This approach is supported by previous research showing that social media platforms like Flickr can serve as valuable resources for observing species distributions and other ecological data[4]. By leveraging photos and antler casts shared by nature photographers and enthusiasts, the researchers were able to gather extensive data over a long period, providing a comprehensive view of the changes in the moose population. In summary, the findings from the Polish Academy of Sciences demonstrate how a hunting ban can lead to significant changes in the phenotypic traits of a species, in this case, the antlers of moose. These results underscore the importance of considering the selective effects of harvest management on wild populations and the potential for passive citizen science to play a crucial role in ecological research.

WildlifeEcologyAnimal Science


Main Study

1) Using public-sourced photos to track changes in moose antler size during a 20-year hunting ban

Published 16th May, 2024

Related Studies

2) Human-induced evolution caused by unnatural selection through harvest of wild animals.

3) The level of habitat patchiness influences movement strategy of moose in Eastern Poland.

4) Passive citizen science: The role of social media in wildlife observations.

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